Thursday, May 21, 2015

Rare African Plant Signals Diamonds in the Soil Below

A Florida geologist has discovered an unusual palm-like plant that only grows in diamond-rich soil.

More specifically, the stilted, thorny Pandanus candelabrum thrives in the potassium-, phosphorous-, and magnesium-rich soil that sits above kimberlite pipes — the volcanic superhighways that deliver precious diamonds from deep within the earth to the surface.


Most of the world’s commercial diamond production is derived from kimberlite pipes and the Pandanus candelabrum plant is the world's only botanical indicator for kimberlite. Where you find this rare plant, you're likely to find diamonds.

Stephen Haggerty, a professor of geophysics at Florida International University in Miami, is credited with making the connection between the palm plant and diamond prospecting. He published his findings in the June-July edition of Economic Geology.


The special connection between kimberlite and the strange plant with stilt-like roots could change the way prospectors in West Africa search for diamonds. Instead of utilizing heavy gear for strip mining, they can simply pinpoint their excavation efforts to where the prickly palm is flourishing — thereby preserving the environment.

Hagerty claims that, until recently, there was no reliable way to locate these small, but concentrated, deposits of diamonds hidden in the remote and dense jungle. Some diamond-rich areas are only a few acres in size.


According to Science magazine, Hagerty’s clever hypothesis is already yielding real results. In a test site inhabited by the Pandanus candelabrum, Hagerty secured four diamonds, two of them around 20 carats apiece.

Interestingly, the palm/diamond association has been played out with other flora and precious materials across the globe.

In 2013, we wrote about Australian researchers who discovered that the roots of eucalyptus trees have the ability to draw up tiny gold particles from deep within the soil, with the gold eventually collecting in the leaves and branches. Finding precious metal in the leaves is a certain indicator of the presence of valuable gold deposits 100 feet or more below the surface.

Science magazine reported that Lychnis alpina, a small pink-flowering plant in Scandinavia, and Haumaniastrum katangense, a white-flowered shrub in central Africa, are both associated with copper. And noted that a the presence of a certain type of grass native to California is a dependable sign of nickel and chromium in the soil.

Credits: Photo of Stephen Haggerty and the Pandanus candelabrum: Uncredited via; Tree by Jakob Fahr/iNaturalist (CC BY-NC) via Wikimedia Commons; Rough diamonds via Getty Images.

Wednesday, May 20, 2015

Gerhard Wagner’s World-Class Collection of Tourmaline to Hit the Auction Block in Dallas on June 7

Gerhard Wagner’s world-class collection of tourmaline — 432 lots in all with some valued at more than $500,000 — will be up for bid at Heritage Auctions in Dallas on June 7.


Wagner, who is known as the “King of Tourmalines,” has been carefully cultivating his museum-quality treasures for decades.

“This is like a king opening the crown jewels to bids from his subjects,” said Jim Walker, Director of Fine Minerals auctions at Heritage. “Collectors are chomping at the bit to obtain just a single piece of his extraordinary collection.”

Some of the top lots of the auction include the following:

“Blue on Blue”tourmaline on tourmaline with quartz from the Porcupine Pocket of the Pederneira Mine, Brazil, shown above (Estimate: $500,000 - $700,000).

Recovered in 2001, this specimen features two major crystal types: thin and long, or stout and wide. The longest thin crystal is an enormously elongated thin blue prism 9.25 x 0.31 inches in size, and there are several shorter ones of similar proportions. The stout tourmalines are approximately 3.93 inches across, and 4.8 inches long. The overall measurements are 5.5 x 9.1 x 6.3 inches.


“Blastoff”tourmaline on cleavelandite from the Grandon Pocket of the Pederneira Mine, Brazil (Estimate: $450,000 -$650,000).

Rising from a pure white base of bladed cleavelandite is a stunning group of multi-colored tourmaline crystals of elongated form. The specimen is composed of roughly six crystals, but the aggregate is strongly dominated by a group displaying a radiating habit with three terminated crystals taking flight from the matrix, hence the name "Blastoff." The overall measurements are 5.6 x 5.4 x 6.6 inches.


“Flower of Pederneira”tourmaline on quartz with lepidolite and cleavelandite from the Proud Pocket of the Pederneira Mine, Brazil (Estimate: $300,000 - $500,000).

This specimen is unique in a number of ways. First, it features a "flower," which is actually a cluster of four crystals attached at the termination of an already superb prism measuring 6.18 inches in length. Of the "flower" cluster, three of the four are double-terminated. A second unusual characteristic is a “bent” crystal measuring 5.31 inches long.

Heritage is promoting the June 7 auction as an opportunity for non-collectors to learn about the beauty and value of the specimens as not just as minerals, but as magnificent pieces of fine art.


“This collection illustrates the fact that the beauty of high-quality mineral specimens make them objects comparable to the most refined forms of art,” wrote Milan-based Mineralogy Museum curator Dr. Federico Pezzotta in the coffee table book, The World of Tourmaline. The publication features 379 vivid images of Wagner’s breathtaking discoveries.

According to Heritage Auctions, Wagner’s passion for collecting fine minerals dates back to his childhood, well before he could ever consider buying any of the specimens that have made him famous.

The fascination that began as a child picking up fossils on the shores of Lake Constance, on the Rhine River in Germany, became a process of education, collecting and patience that have led to him being one of the most respected and well-liked names in the business, noted the auction house.

Images: Heritage Auctions.

Tuesday, May 19, 2015

Watch a Scientist Set a Diamond Ablaze in This Fascinating Lab Experiment

Sitting on its lofty perch atop the Mohs scale, diamond is the hardest naturally occurring material known to man. It is harder than a ruby, sapphire or emerald and has the ability to slice through steel like a hot knife through butter. The only substance that can scratch a diamond is another diamond.


Under normal circumstances, diamonds truly are forever. But in the labs of the British Royal Institution, the famous De Beers ad slogan — not to mention the theme of the Shirley Bassey hit song — has been put to the test.

Because a diamond is made of pure carbon, scientists have theorized since the 1700s that a diamond should burn like other carbon materials, such as graphite or coal.

And, indeed, during the early 1770s, French chemist Antoine Lavoisier used two powerful lenses to magnify the sun’s rays directly onto a diamond. The diamond slowly disappeared and carbon dioxide gas accumulated, proving that the diamond was made from carbon.

In the video below, British scientist and author Peter Wothers enlists the help of Nobel prize-winning chemist Sir Harry Kroto to demonstrate what it takes to get a diamond to burn.


Wothers adds a bit of drama and comic relief by using Kroto’s wife’s engagement diamond for the experiment. The viewer can see Kroto getting increasingly more uncomfortable as it becomes very clear that his wife’s diamond — under the right conditions — will ignite.


In pure oxygen, diamonds can ignite at 1320 degrees F. In normal conditions, the ignition occurs at about 1520 degrees F.

Wother’s experiment is conducted in a chamber of pure oxygen. The resulting gases are collected in a tube leading to a beaker of limewater. The experiment anticipates that if the burning material contains carbon, the smoke will contain carbon dioxide. When the carbon dioxide mixes into the limewater, it turns the mixture a milky white color — basically delivering calcium carbonate, an antacid used to calm a sour stomach.


Wother’s does his first experiment using a bit of graphite, which he easily ignites using a torch. Then he ups the ante by doing the exact same experiment using the Kroto engagement diamond.


Surprisingly, that lights up, too. The diamond burns as a golden ember without producing any flames. At this point, Kroto half-jokingly comments that he hopes the show can pay for a replacement diamond.

As you might have figured out by now, Wother had cleverly swapped the Krotos’ engagement diamond with a much lower quality specimen before the experiment began.

If you’re worried about how a diamond is protected when a ring needs to be retipped, for example, be assured that jewelers go to great lengths to make sure that the extreme heat of the torch does not affect the gemstone. Some jewelers use boron to protect the stone while others depend on the pinpoint accuracy of a laser welder to keep the diamond out of harm’s way.

Kroto won his Nobel Prize in Chemistry in 1996 for his work in discovering fullerenes, a pure carbon molecule that takes a shape similar to a soccer ball. Recent research has suggested many uses for fullerenes, including medical applications, superconductors, fiber-optics systems and nanotechnology.

Check out Wother’s diamond-burning experiment here…

Images: YouTube screen captures.

Monday, May 18, 2015

35.1-Carat Kashmir Sapphire Sets Per-Carat Record at Christie’s Geneva

Displaying the velvety blue hue of a peacock’s neck feathers, a 35.09-carat Kashmir sapphire set a new record at Christie’s Geneva last week when it fetched $7.4 million — crushing the pre-sale high estimate of $4.3 million.


The gem’s per-carat selling price of $209,689 established a new high-water mark for a Kashmir sapphire, narrowly edging out a record set one day earlier at Sotheby’s Geneva. That Kashmir sapphire, a 30.23-carat stunner, had sold for $6.1 million, or $201,786 per carat.

The cushion-shaped record-setting sapphire was set in a ring with triangular-cut diamond shoulders and baguette-cut diamonds accents. An anonymous Asian bidder made the purchase via phone.


Other highlights from the Christie’s auction included the top lot of the night — a 5.18-carat rectangular-cut fancy vivid pink diamond that sold for $10.8 million, or $2.1 million per carat. The hammer price was on the lower end of the pre-sale estimate of $10.2 million to $13.4 million.


The pink stone, which was purchased by an anonymous buyer, is set in a ring with an oval-shaped surround of colorless oval-cut diamonds.


Selling for $9.03 million, or $162,711 per carat, was this stunning pear-shaped flawless Type IIa diamond weighing 55.5 carats. It was purchased by an Asian private buyer via telephone and the hammer price was within the pre-sale estimate of $8.5 million to $10 million.

Type IIa diamonds are considered the purest of all diamonds because they are composed solely of carbon with virtually no trace elements in the crystal lattice.


The biggest disappointment of the Christie’s Geneva sale was a 19th century diamond brooch linked to Spain's royal family. Featured on the cover of the auction house’s catalog, the final bid of 900,000 Swiss francs (about $982,000) failed to reach the secret reserve price set by the seller, thus going unsold.

The brooch had been given by Spain's King Alfonso XII to the Archduchess Maria Christina of Austria for their wedding in 1879 and remained with the family until the 1980s.

Credit: Christie's Images Ltd. 2015